Sea Ledger, September 2020

2020-09-01 to 2020-09-30 · archive

issued: 653
warning-days in force: 9,587
in force at month end: 318
sea × type cells: 230

baseline: same month, previous 5 years (2019-09, 2018-09, 2017-09, 2016-09, 2015-09)

By type

type	issued	warning-days	in force at end
Exercises	178	1,653.2	45
Icebergs	90	96.1	4
Incidents	77	945.4	27
Nav aids	52	1,799.9	67
Missiles	50	425.3	16
Surveys	45	1,668.8	59
Quakes	38	124.4	0
Cable ops	28	350.7	15
Other	23	398.6	13
Derelicts	20	117.9	3
Storms	15	20.6	0
Wrecks	12	1,400.7	50
Spills	11	199	7
Debris	7	51	1
Structures	4	39.7	3
Piracy	3	28	0
Mines	0	30	1
Restricted	0	90	3
Volcanic	0	90	3
Containers	0	27.2	0
Ordnance	0	30	1

By sea and type · 200 cells, most issued first

cell	issued	warning-days	at end	longest d	vs 5 y
Icebergs · Labrador Sea	30	35	2	31	1.2× / 25.4
Icebergs · South Atlantic Ocean	30	30.1	1	30	1.3× / 22.6
Icebergs · Southern Oceansurge	29	28	1	30	2.6× / 11
Exercises · Black Sea	23	296.7	5	120	1.6× / 14
Exercises · North Pacific Ocean	22	136.9	3	65	0.8× / 28.2
Incidents · North Pacific Ocean	19	226.7	9	45	0.8× / 24.2
Exercises · Mediterranean Sea - Eastern Basin	16	182.4	5	272	1.0× / 15.8
Quakes · South Pacific Ocean	16	50.9	0	—	0.8× / 20
Incidents · South China Sea	15	232	3	234	0.6× / 25.8
Storms · Gulf of Mexicosurge	15	20.6	0	—	8.3× / 1.8
Exercises · South Atlantic Ocean	14	124.6	4	34	1.1× / 12.4
Exercises · Philippine Seasurge	14	25	1	26	2.6× / 5.4
Missiles · North Atlantic Oceansurge	13	49	3	33	2.5× / 5.2
Missiles · Black Seasurge	12	233.8	6	32	2.6× / 4.6
Exercises · Arabian Sea	12	87	2	34	1.9× / 6.4
Missiles · Indian Oceansurge	12	30.3	3	33	10× / 1.2
Cable ops · North Atlantic Ocean	10	37.7	3	33	1.7× / 5.8
Exercises · Aegean Sea	9	196.8	6	275	1.0× / 8.8
Exercises · Bay of Bengal	9	68	3	33	0.9× / 10
Exercises · North Atlantic Ocean	8	57.9	4	62	0.8× / 9.6
Exercises · Yellow Sea	8	48.8	1	33	1.3× / 6.4
Other · Bay of Bengalnew	8	14.2	0	—	new / 0
Surveys · Bay of Bengalsurge	8	10	1	20	4.4× / 1.8
Nav aids · South Atlantic Ocean	7	255.1	7	187	0.8× / 9.2
Exercises · Mediterranean Sea - Western Basinsurge	7	45.7	3	272	18× / 0.4
Missiles · Barentsz Sea	7	33.9	2	22	0.9× / 7.4
Nav aids · North Pacific Oceanlong running	6	121.6	7	425	1.5× / 4
Spills · Gulf of Mexico	6	77	4	44	1.0× / 5.8
Exercises · South Pacific Ocean	6	38.2	1	32	0.8× / 7.6
Nav aids · South Pacific Oceanlong running	5	218.1	8	695	1.9× / 2.6
Surveys · Mediterranean Sea - Eastern Basin	5	164.5	5	102	0.8× / 6.4
Incidents · Laccadive Seasurge	5	71.6	0	—	3.1× / 1.6
Surveys · South Atlantic Ocean	5	63.8	2	49	0.5× / 11
Nav aids · North Sea	5	60	4	61	0.6× / 8
Nav aids · The Northwestern Passagessurge	5	5.7	1	28	13× / 0.4
Incidents · Coral Sea	5	0.7	0	—	0.9× / 5.8
Nav aids · Caribbean Sea	4	427.5	15	250	1.1× / 3.6
Surveys · Persian Gulflong running	4	118.6	3	491	1.4× / 2.8
Exercises · Barentsz Seasurge	4	48.1	1	98	2.9× / 1.4
Cable ops · South Atlantic Ocean	4	43.8	1	47	1.5× / 2.6
Exercises · Japan Seasurge	4	30.3	1	19	10× / 0.4
Exercises · Andaman or Burma Seasurge	4	17.9	1	30	2.9× / 1.4
Quakes · Coral Seasurge	4	12	0	—	4.0× / 1
Quakes · North Pacific Ocean	4	12	0	—	0.5× / 7.8
Derelicts · North Atlantic Ocean	4	10	0	—	1.4× / 2.8
Structures · South Atlantic Oceansurge	4	9.7	2	28	20× / 0.2
Nav aids · Davis Strait	4	1.9	0	—	1.5× / 2.6
Wrecks · Arabian Seasurgelong running	3	103.4	6	372	2.5× / 1.2
Cable ops · North Pacific Oceansurge	3	54.8	2	31	15× / 0.2
Surveys · Arabian Sea	3	46.2	3	26	1.7× / 1.8
Exercises · English Channelsurge	3	45.9	0	—	15× / 0.2
Incidents · Tyrrhenian Seanew	3	40.8	3	18	new / 0
Spills · North Atlantic Ocean	3	37	1	41	1.1× / 2.8
Incidents · Bay of Bengalsurge	3	33.7	2	35	3.8× / 0.8
Incidents · Mediterranean Sea - Eastern Basin	3	22	1	46	0.3× / 11.4
Surveys · Aegean Seasurge	3	20.9	2	13	5.0× / 0.6
Exercises · Chukchi Seanew	3	13.5	0	—	new / 0
Exercises · Persian Gulfnew	3	11.4	0	—	new / 0
Quakes · North Atlantic Oceansurge	3	10.9	0	—	2.5× / 1.2
Quakes · Philippine Sea	3	9	0	—	1.1× / 2.8
Incidents · South Atlantic Ocean	3	9	0	—	0.4× / 7.2
Wrecks · Inner Seas off the West Coast of Scotlandnew	3	7.6	3	5	new / 0
Derelicts · South Atlantic Ocean	3	7.6	0	—	1.5× / 2
Derelicts · Bay of Bengal	3	7.1	0	—	1.1× / 2.8
Other · Gulf of Alaskasurge	3	2.4	1	25	7.5× / 0.4
Surveys · North Atlantic Oceanlong running	2	283.6	10	1,049	0.3× / 5.8
Nav aids · North Atlantic Oceanlong running	2	157.1	4	417	0.4× / 5.6
Incidents · North Atlantic Oceanlong running	2	61.4	3	383	0.2× / 12.6
Surveys · Mediterranean Sea - Western Basinnew	2	57.4	2	98	new / 0
Cable ops · South China Sea	2	46.8	1	205	0.9× / 2.2
Exercises · Laccadive Sea	2	38.4	1	33	1.0× / 2
Incidents · Indian Ocean	2	30.4	0	—	0.4× / 5.4
Piracy · Gulf of Guinea	2	21	0	—	3.3× / 0.6
Incidents · South Pacific Ocean	2	20.2	0	—	0.3× / 6.8
Other · English Channel	2	19.9	1	27	2.5× / 0.8
Missiles · South Pacific Ocean	2	12.4	0	—	0.9× / 2.2
Quakes · Indian Ocean	2	8.7	0	—	1.1× / 1.8
Other · Mediterranean Sea - Eastern Basin	2	6.7	1	6	5.0× / 0.4
Derelicts · Laccadive Sea	2	6.1	0	—	2.5× / 0.8
Quakes · Banda Sea	2	6	0	—	2.5× / 0.8
Debris · English Channel	2	6	0	—	10× / 0.2
Debris · Indian Ocean	2	6	0	—	5.0× / 0.4
Derelicts · Mozambique Channel	2	6	0	—	2.0× / 1
Incidents · Timor Sea	2	5.8	1	20	5.0× / 0.4
Wrecks · Indian Ocean	2	5.4	0	—	10× / 0.2
Derelicts · Mediterranean Sea - Western Basin	2	5.3	1	20	1.7× / 1.2
Incidents · Bismarck Sea	2	4.7	0	—	2.0× / 1
Other · The Coastal Waters of Southeast Alaska and British Columbianew	2	3.5	1	3	new / 0
Wrecks · Laptev Seanew	2	1.9	0	—	new / 0
Nav aids · Beaufort Sea	2	0.4	0	—	10× / 0.2
Nav aids · Gulf of Mexico	1	97.6	4	251	0.2× / 4.2
Other · Caribbean Sealong running	1	90	3	1,349	new / 0
Surveys · Kara Sea	1	88.5	3	61	0.6× / 1.8
Surveys · Black Sea	1	78	3	105	0.4× / 2.4
Nav aids · Mediterranean Sea - Western Basin	1	65.8	3	122	2.5× / 0.4
Surveys · Arctic Ocean	1	62.8	2	356	1.0× / 1
Wrecks · South Atlantic Ocean	1	61	2	65	1.7× / 0.6
Surveys · South China Sealong running	1	51.9	2	384	0.4× / 2.8
Surveys · Indian Ocean	1	50.3	1	36	1.0× / 1
Cable ops · North Sea	1	48.3	1	47	0.2× / 6
Incidents · Java Sea	1	47.1	1	205	0.7× / 1.4
Nav aids · Arabian Sea	1	47	1	328	0.7× / 1.4
Cable ops · Persian Gulf	1	46.3	2	43	1.7× / 0.6
Incidents · Caribbean Sea	1	44.4	1	141	0.1× / 6.6
Derelicts · Arabian Sea	1	43.5	1	250	1.0× / 1
Surveys · South Pacific Ocean	1	39.9	2	364	new / 0
Surveys · Sea of Marmara	1	33.5	1	47	1.7× / 0.6
Debris · Celtic Sea	1	33	1	37	5.0× / 0.2
Spills · North Pacific Ocean	1	32	1	31	0.6× / 1.6
Spills · The Coastal Waters of Southeast Alaska and British Columbia	1	31	1	35	1.3× / 0.8
Surveys · English Channel	1	30	1	53	5.0× / 0.2
Wrecks · Sea of Okhotsk	1	27.6	1	27	new / 0
Cable ops · Aegean Sea	1	24.5	1	24	new / 0
Cable ops · Black Sea	1	21.5	1	21	new / 0
Incidents · Mediterranean Sea - Western Basin	1	20.3	0	—	0.8× / 1.2
Incidents · Gulf of Thailand	1	18.5	1	18	1.3× / 0.8
Missiles · North Pacific Ocean	1	15.3	0	—	0.1× / 11.2
Other · East Siberian Sea	1	14.5	0	—	new / 0
Other · Gulf of Mexico	1	14.5	0	—	5.0× / 0.2
Incidents · Ionian Sea	1	13.2	1	13	5.0× / 0.2
Nav aids · Irish Sea and St. George's Channel	1	11.5	0	—	0.3× / 4
Cable ops · Philippine Sea	1	11	0	—	1.7× / 0.6
Other · Bering Sea	1	9.4	0	—	2.5× / 0.4
Nav aids · Great Australian Bight	1	9.1	1	9	0.4× / 2.4
Exercises · Kara Sea	1	8.5	0	—	new / 0
Exercises · Laptev Sea	1	8.4	0	—	new / 0
Surveys · The Northwestern Passages	1	8.3	1	8	2.5× / 0.4
Nav aids · Hudson Bay	1	8.1	0	—	new / 0
Nav aids · Gulf of Guinea	1	8	0	—	new / 0
Nav aids · Gulf of California	1	7.6	1	7	5.0× / 0.2
Exercises · Gulf of Guinea	1	7.1	0	—	new / 0
Piracy · Yellow Sea	1	7	0	—	new / 0
Nav aids · Alboran Sea	1	6.5	1	6	5.0× / 0.2
Cable ops · English Channel	1	5.9	0	—	new / 0
Quakes · South Atlantic Ocean	1	5.9	0	—	0.6× / 1.8
Nav aids · Hudson Strait	1	5.8	1	5	new / 0
Exercises · Indian Ocean	1	5.7	0	—	1.0× / 1
Cable ops · Caribbean Sea	1	5.1	1	36	2.5× / 0.4
Missiles · Laccadive Sea	1	4.8	0	—	0.6× / 1.6
Surveys · Greenland Sea	1	4.6	1	4	5.0× / 0.2
Surveys · North Pacific Ocean	1	4.6	1	4	new / 0
Nav aids · Mozambique Channel	1	4.5	0	—	new / 0
Incidents · Great Australian Bight	1	3.6	0	—	5.0× / 0.2
Missiles · South China Sea	1	3.2	0	—	new / 0
Other · Beaufort Sea	1	3	0	—	1.3× / 0.8
Derelicts · Coral Sea	1	3	0	—	1.7× / 0.6
Incidents · Davis Strait	1	3	0	—	0.6× / 1.8
Debris · Gulf of Mexico	1	3	0	—	new / 0
Derelicts · Indian Ocean	1	3	0	—	0.2× / 4.8
Other · Irish Sea and St. George's Channel	1	3	0	—	1.7× / 0.6
Icebergs · Kara Sea	1	3	0	—	0.3× / 3.2
Quakes · Mediterranean Sea - Eastern Basin	1	3	0	—	new / 0
Quakes · Molukka Sea	1	3	0	—	2.5× / 0.4
Quakes · Sea of Okhotsk	1	3	0	—	new / 0
Debris · Timor Sea	1	3	0	—	2.5× / 0.4
Exercises · Caribbean Sea	1	2.9	0	—	0.8× / 1.2
Cable ops · Eastern China Sea	1	2.5	1	2	2.5× / 0.4
Surveys · Ionian Sea	1	2.5	0	—	new / 0
Cable ops · Mediterranean Sea - Eastern Basin	1	2.5	1	2	1.3× / 0.8
Surveys · Gulf of Guinea	1	2.4	1	2	new / 0
Exercises · Gulf of Mexico	1	1.9	0	—	0.7× / 1.4
Incidents · Solomon Sea	1	1.8	0	—	0.6× / 1.6
Incidents · Arabian Sea	1	1.7	1	1	0.3× / 3.2
Missiles · Sea of Azov	1	1.5	1	1	new / 0
Incidents · Savu Sea	1	1.3	0	—	new / 0
Derelicts · South Pacific Ocean	1	1.3	1	1	1.3× / 0.8
Exercises · Coral Sea	1	0.9	0	—	1.3× / 0.8
Nav aids · English Channel	1	0.1	0	—	0.3× / 3.2
Incidents · Tasman Sea	1	0	0	—	0.8× / 1.2
Wrecks · South China Sealong running	0	270	9	591	0.0× / 1
Wrecks · Caribbean Sealong running	0	240	8	1,339	0.0× / 0.8
Wrecks · Persian Gulflong running	0	210	7	455	— / 0
Wrecks · North Atlantic Oceanlong running	0	150	5	1,063	0.0× / 0.8
Surveys · Sea of Okhotsk	0	92.4	3	177	0.0× / 1.6
Exercises · Ionian Sea	0	90	3	275	0.0× / 0.2
Wrecks · North Pacific Oceanlong running	0	90	3	1,202	0.0× / 0.2
Surveys · North Sea	0	78.5	2	53	0.0× / 4.2
Surveys · Norwegian Sea	0	71.1	1	148	0.0× / 1.2
Nav aids · Andaman or Burma Sealong running	0	60.4	2	489	0.0× / 0.6
Wrecks · Gulf of Mexicolong running	0	60	2	1,294	0.0× / 0.2
Restricted · South Atlantic Ocean	0	60	2	272	0.0× / 1.2
Other · South Pacific Ocean	0	60	2	195	0.0× / 0.4
Wrecks · South Pacific Ocean	0	60	2	244	0.0× / 1.2
Other · Arabian Sealong running	0	47.8	1	523	0.0× / 0.2
Missiles · Aegean Sea	0	30	1	116	0.0× / 0.4
Surveys · Balearic (Iberian Sea)	0	30	1	62	0.0× / 0.4
Surveys · Barentsz Sea	0	30	1	110	0.0× / 1.6
Surveys · Bass Strait	0	30	1	58	0.0× / 0.2
Nav aids · Bay of Bengal	0	30	1	112	0.0× / 1.6
Surveys · Beaufort Sea	0	30	1	301	0.0× / 0.4
Surveys · Bering Sealong running	0	30	1	388	0.0× / 0.4
Surveys · Caribbean Sea	0	30	1	51	0.0× / 2
Volcanic · Caribbean Sea	0	30	1	107	— / 0
Nav aids · Gulf of Thailand	0	30	1	349	— / 0
Nav aids · Inner Seas off the West Coast of Scotland	0	30	1	293	0.0× / 3.2
Nav aids · Laccadive Sealong running	0	30	1	516	0.0× / 0.4
Nav aids · Mediterranean Sea - Eastern Basin	0	30	1	55	0.0× / 0.2
Volcanic · Mozambique Channel	0	30	1	363	0.0× / 0.2
Other · North Atlantic Ocean	0	30	1	77	0.0× / 2.2
Other · North Pacific Ocean	0	30	1	57	0.0× / 5.2

Cite: seahazards.com Sea Ledger, 2020-09, retrieved 2026-09-03

Not for navigation. Warning-days = days each warning was in force within the month, summed. Only warnings we display are counted; the ratio compares warnings issued with the mean of the reference months.